There are various media via which data can be communicated including terrestrial and satellite radio frequency signals for both broadcast systems and cellular mobile communication systems where mobile terminals communicate using radio signals to a network of base stations. Another media for communicating data is a cable network which can be a coaxial cable or a fibre optic in which data is modulated and communicated through the cable. Cable systems can be used to form broadcast systems in which a Cable Modem Termination System (CMTS) or head end modulates data onto signals for transmission through the cable network to a receiver which is known as a Cable Modem (CM). An example of a cable modem system which has been developed for the communicating data including television signals via a cable network is the Data Over Cable Service Interface Specifications (DOCSIS) system which is administered by the cable labs. DOCSIS 3.0 for example provides a physical layer and a media access layer specification for arranging for data to be communicated via a cable network. The specification provides various communication techniques between the CMTS and the CMs for efficiently using an available bandwidth within the cable network.
There are various applications for the communications of the data via a cable network. These applications increase in variety and include video transmission, voice transmission, gaming and data communications generally. In order to allow access of the CMs to the upstream communications resources it is necessary to provide an arrangement of the cable network system to the effect that the CMs can request access to upstream communications resources for communicating data from the CM to the CMTS.
It will therefore be appreciated that with respect to known cable network communication systems it is desirable to provide an improved cable network communications system which makes an efficient use of communications resources by reducing signalling overheads and optimises a round trip delay time for accessing upstream communications resources.